Using e+e- annihilation data collected by the CLEO II detector at CESR we have observed the decay D+s→ωΠ. This final state may be produced through the annihilation decay of the D+s or through final state interactions. We find a branching ratio of γD+s→ωΠ/D+s→ηΠ=0.16α0.04±0.03 where the first error is statistical and the second is systematic.
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Recently, there has been considerable interest in the decay D + --'11' n + ~1 due to conflicting measurements of the branching ratio relative to the decay D~--. 0n + \[1 -4\]. A precise measurement of this decay rate is of interest since a large D~+ -,q'n + branching ratio poses problems for current models, which predict values of BR(D~ + ~'n +)/BR(D + ~0n +) of less than 2 \[5 ,6 \]. Among the mechanisms offered as possible explanations for larger values are final-state interactions and even the presence of a nearby scalar resonance \[5 ,7 \]. Several experiments have searched for evidence of the decay D~+ ~l\]'n +. An indication for a signal was reported by Mark II \[1 \], with a value of 4.8 + 2.1 for the ratio BR(D + --,Tl'n +)/BR(D + --.0n +). Subsequently, NA14' also claimed evidence for this channel, with a value of 5.0 + 1.8 + 1.2 for the same ratio \[3\]. However, in considerable disagreement with these results are the upper limits reported by Mark III and E691. These experiments have determined BR(D + ~l\]'n + )/BR(D + ~0n + ) to be less than 1.9 \[2\] and less than 1.7 \[4\] respectively, both at the t Supported by the German Bundesministerium f'tir Forschung und Technologie, under contract number 054DO51P. 2 Supported by the German Bundesministerium f'tir Forschung und Technologie, under contract number 054ER 12P. 3 Supported by the German Bundesministerium f'tir Forschung und Technologie, under contract number 054HD24P. 4 McGill University, Montreal, Quebec, Canada H3C 3J7. 5 University of Toronto, Toronto, Ontario, Canada M5S IA7. 6 Carleton University, Ottawa, Ontario, Canada K1S 5B6. 7 Supported by the Natural Sciences and Engineering Research Council, Canada. 8 Supported by the German Bundesministerium f'dr Forschung und Technologie, under contract number 054KA 17P. 9 Supported by Alexander yon Humboldt Stiftung, Bonn, FRG. 1o Supported by Raziskovalna skupnost Slovenije and the Inter-nationales Biiro KfA, Jiilich. 11 Supported by the Swedish Research Council. 12 Supported by the US Department of Energy, under contract DE-AS09-80ER 10690. at References in this paper to a specific charged state are to be interpreted as implying the charge-conjugate state also.